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P. H. FIELDING. ATTACHMENT PLUG. APPLICATION FILED JUNE 21 1903 no MODEL.

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, UNiTED STATES Patented February 23, 1904.

PHILIP H. FIELDING, or NEW YORK, N.- Y.

- A TACHMENT-PLUG.

SPECIFICATION forming part of Letters Patent No. 752,833,'dated February 23, 1904 Application filed-Tune 27, 1908. SerialNo. 163,349. (No model.) i

Be it known that I, r mn. FIELDING, a citizen of the United States, residing at the city. of New York, in the borough of. Manhattan and State ofNew 'York, have inventedcertainnew and usefullmprovements in Attach; merit-Plugs, of which the following is a full, clear, and exact description. i

This invention relates to devices which are commonlyattached to the end of a flexible electric conductor for the purpose of'connecting. a translatingdevice withasour'ceof electricity' and known as i attachmentplugs. These devices usually consist of ablock or base of porcelain or other s'uit'abl'einsulating mate: rial carrying binding-screws for securingfthe ends of the' flexible conductor and havinga projection or block upon which are mounted metallic parts, which serve the double purpose of mechanically connecting the plug with a socket and electrically connecting the binding devices on the plug or base with thosein the In my improved attachment-plug the connections for the flexible conductor are wholly within the. plug itself and amply covered and protected thereby, the construction neverthe: less being such .thatthe conductors can be readily attached and detached as required and arranged to preventstrains upon the conductor from being communicated to the binding devices. a

The details of my improved attachmentplug will be described with reference to the accompanying drawings, in which Figure 1 is a side elevation of the plug. Fig. 2 is a longitudinal section thereof. Fig. 3 is asection of the shell of the plug with the core removed; Fig. 4, two side views of the core, and Fig. 5 a cross-section of the core on line as w of Fig. 4.

My improved attachment-plug has the same general shape of the ordinary attachmentplugs in that it consists of a thickened disk part a and a central cylindrical projection I) from one face thereof; The disk part a is used as a knob to manipulate the device when attaching or detaching it to and from its socket and in the old forms. This part also carries ing-wires are vicethe blnding-screws are not attachedtd upon it binding-screws, to which the conductttached; but in the present dethe disk. The projection?) is provided with an axial chambero of such diameter-as to leave the walls of the projection comparatively i thin, but of sufficient mechanical strength; This chamber extends into the disk portion and. is continued through the bottom thereof:

having a suitable shape to mechanically en,

gage with a socket, into which it fits. x The sleeve here shown-is provided with azcrossthread and is similar to an ordinary=li1d1sonv I sleeve d and extends thence downwardand into the chamber 0, where it rests against the side thereof. "It is provided with akink'd to act as a latch, as willhereinafter belex plained.

On one side of the projection b This plate is solderedor 6 is-a cylindrical core ofporcelain orother suitable insulating material having an exterbody ofthe core for a purpose whichwillhere inafter appear; In each of these grooves fixed a metallic plate f and g, respectively.-

The former carries a binding-screw f and is bent laterally to enter a recess in the upper end of the core, where it is caught by an axial screw '5, which enters the top of the core and at the same time confines a central contactplate 1: on the extreme end of the core. The plate 9 carries a binding-screw g and has an ear g bent laterally to enter another recess in the porcelain, as shown in Fig. 5, and there caught and held by a countersunk screw g entering the side of the core to hold the plate in place. The upper end of plate 9 is returned and providedwith a depression or bend 9, adapted to receive the kink 0Z in'the plate d. The lower end of the extended partition 6' is provided with two transverse holes 6 and 6 The flexible conductor is secured to the attachment-plug in the following manner: First,

the conductor (indicated by p and p) is passed through the opening and brought out through and above the chamber c.- The two wires are then passed, respectively, in opposite directions through the holes e and e of the core. Then the ends of the wires are"stripped' of their insulation, and one of them is fastened by the binding-screw f, while the other is fastened by the binding-screw g. The naked parts of the wires are then separated from each other by the extended partition 6'. The

conductor is now pulled backward and the core inserted into the chamber 0 through the open upper end, the core being so placed that plate g will be presented to the plate d. The

core is shoved home and caught in its final position by the engagement of the plate d with the plate g. Thus the external cylinder d and the external center contact i become the respective terminals of the wires 10 and p. The device now presents the appearance shown in Fig. 1, where, it will be observed, the binding-screws and connection devices are entirely covered and housed, so that short clrcuits are v impossible by reason of contact of foreign bodies with interior parts of the plug while the latter is in its socket. It is understood that this plug is adapted to be used in connection with an incandescent-lamp socket or any electrical outlet socket for the plug.

' Whenever it is. necessary to readjust the flexible cord,the core can be readily. withdrawn provided with a suitable v by means of forceps applied under the center which tends to detach the cord; but in my deviceitwill be seen that the cord in passing laterally through the openings 6 and e of the core/before it reaches the binding-screws is suspended by the core and the strains to which the cord is subjected are not communicated to the binding device. The result is that the plug is not-liable to become detached from the cord. It is also pointed out that since the plug or core to which the flexible conductor is attached is confined in a chamber of the body part, which is closed at the rear, the plug cannot be detached from the body part by pulling on a cord, as would be the case if the plug entered from the rear.

Having described my invention, I claim 1. An attachment-plug consisting of a base of insulating material, having a cylindrical projection surrounded by a metallic sleeve and having an axial chamber opening at the outer end of said projection, in combination with a plug removably fitted into said chamber and carrying two binding devices and an exposed contact, said binding devices being respectively connected with the sleeve and the exposed contact,and a flexible conductor attached to the binding devices and leading rearward through the base, substantially as described.

2. An attachment-plug consisting of a base of insulating material having a cylindrical projection surrounded by a metallic sleeve and having an axial chamber opening at the outer end of the projection, in combination with a plug removably fitted into said chamber and carrying two binding devices for electrical conductors, means for connecting one of the binding devices with said sleeve and a contact on the end of the plug connected with the I other binding device and exposed. at the end of the projection, substantially as described.

3". An attachment-plug consisting of abase of insulating material having an integral cylindrical projection therefrom containing an axial chamber, a metallic sleeve surrounding vsaid projection, a plate connected with said sleeve and extending into said chamber and a core removably fitted to said chamber and provided with two contacts, one of which is exposed outside when the plug is in place and the other adapted to engage said plate, and binding devices for electric wires; connected with said contacts.

In witness whereof I subscribe my signature in presence of two witnesses. v

PHILIP H. FIELDING. Witnesses:

FRANK S. OBER, WALDO M. CHAPIN. 

